Figure 2. Photos of top and back faces of a representative sample (at perforation) for each one of the configurations tested. Prepreg and autoclave processing. Figure 3. Photos of top and back faces of a representative sample (at perforation) for each one of the configurations tested. NCF and VARTM. supported by a ring support with a 75 mm internal diameter. Each specimen was impacted with a 20mm hemispherical indenter using a drop-weight tower. Force vs time data were recorded through a load cell mounted in proximity of the impactor tip. Subsequently, the velocity, displacement and absorbed energy were calculated following the procedure reported in the ASTM D7136/ D7136M test standard19 . In order to estimate the perforation energy, each set of 5 samples was impacted with progressively increasing energy until full perforation of the laminate was achieved. The different impact energies were obtained by mainly changing the mass of the impactor while maintaining a narrow range of impact heights. This www. sampe.org is to limit the effect of stress waves which becomes predominant at increasing impact speeds. Hence, the impact speed was kept within a range of 2,7 and 3.13 m/s. Small adjustment in impact speed were necessary to fine tune the impact energy aiming at measuring the perforation threshold. RESULTS Table 2 reports mean and max/min values of peak load, displacement at the peak load, energy dissipated before the peak load and perforation energy for the samples tested under LVI. Figure 2 and Figure 3 shows photographs of representative samples for each configuration taken from the top and bottom of each sample to highlight MARCH APRIL 2023 | SAMPE JOURNAL | 15http://www.sampe.org